Present day satellite communication systems conventionally employ orthogonally polarized signals for effecting two-way communications over the same channel. In general, one polarization (e.g. vertical) is assigned for signalling in one direction (e.g. earth station W (West)-satellite-earth station E (East)) while the other polarization (e.g. horizontal) is assigned for signalling in the opposite direcion (e.g. earth station E (East)-satellite-earth station W (West)). FIG. 1 shows a typical earth station having an antenna 11 and attendant feed 12, which is coupled via a section of cylindrical waveguide 13 to an I/O port 14 of an orthomode coupler 15. Orthomode coupler 15 has a first input port 16 to which a section of rectangular waveguide 18 is coupled. Waveguide section 18 couples transmit signals of a first polarization (e.g. horizontal) to input port 16. A separate section of rectangular waveguide 19 is coupled to an output port 17 of orthomode coupler 16 for coupling received signals of a second polarization (e.g. vertical), orthogonal to the first polarization, to receive/down conversion equipment (e.g. a downstream LNA). At the remote site earth station the polarizations for transmit and receive signals are reversed, so that the port connections are opposite those of FIG. 1.
As the number of applications for satellite usage increases, the desirability of taking advantage of both polarizations for additional signalling capability has been proposed. For example, a service industry facility, such as a hotel, may desire to add teleconferencing, video reception capability to its communication link, as by way of a horizontally polarized receive link. Unfortunately, because of packaging and mounting constraints on the orthomode coupler, it is often not possible to gain physical access to the downstream waveguide coupling hardware (e.g. rectangular waveguide section 18) for splitting off an additional (receive) horizontal polarization.